Immunofluorescence is a highly specific and sensitive method for use in the study, diagnosis and treatment of human disease. In this Phase I project. Zotic Inc. proposes to develop a novel fluorescent dye Princeton Red-ITC (PRITC) for use in fluorescence immunoassays. The fluorochrome will have the following characteristics: 1) large stoke's shift. 2) excitation maximum around 490 nm, 3) low molecular weight, 4) high quantum yield. and 5) an activated group for linking to antibodies and other biological molecules. The fluorochrome will be synthesized and conjugated to a variety of antibodies. The fluorochrome-antibody conjugates will be tested in direct and indirect fluorescent immunoassays and evaluated by fluorescence microscopy and flow cytometry. The antibody-fluorochrome will be evaluated in dual color fluorescent assays using fluorescein-labeled antibodies as the companion dye. Dual color analysis with fluorescein will be performed at one excitation wavelength. PROPOSED COMMERCIAL APPLICATION: Any reagents generated through the proposed work, such as activated fluorochromes or fluorochrome-conjugated secondary reagents, will be marketed directly to the research community. Zotic also may develop licensing agreements with other companies to provide fluorochromes and fluorescent proteins for use with specific instruments, reagents, or assay kits. In Phase II, Zotic will use these fluorochromes and reagents to develop kits of matched reagents for immunofluorescence detection of tumor cells.